Fuel cell unit and fuel cell stack

Abstract

The present disclosure relates to a fuel cell unit and a fuel cell stack, the fuel cell unit comprising: two polar plates, the polar plates comprising gas flow channel surfaces and liquid flow channel surfaces arranged oppositely, the gas flow channel surfaces comprising a plurality of gas flow channel units, the gas flow channel units enabling gas to flow from a center position to an edge, the plurality of gas flow channel units being arranged in an array; the liquid flow channel surfaces comprising a plurality of liquid flow channel units, the plurality of liquid flow channel units being arranged one-to-one with the plurality of gas flow channel units; and a membrane electrode assembly arranged between the gas flow channel surfaces of the two polar plates. The technical scheme of the present disclosure effectively solves the technical problem of poor thermal uniformity of a conventional fuel cell stack.

Description

Technical Field

[0001] This disclosure relates to the field of household appliances, and more particularly to a fuel cell unit and a fuel cell stack. Background Technology

[0002] A proton exchange membrane fuel cell (PEMFC) is a novel energy device that converts chemical energy into electrical energy through the electrochemical reaction of hydrogen and oxygen. It boasts advantages such as high energy conversion efficiency, zero pollution, low operating temperature, and rapid start-up. A fuel cell stack typically consists of multiple fuel cell cells stacked together and clamped together by end plates. Each cell comprises a first electrode plate, a membrane electrode assembly (MEA), and a second electrode plate, forming a "sandwich" structure. By stacking multiple layers of cells into a stack, different voltage and output power requirements can be met. The MEA is a three-in-one component consisting of a diffusion layer, a catalytic layer, and a proton exchange membrane. The diffusion layer provides a mass transfer channel for the reactant gases and also acts as a current collector; the catalytic layer is the site of the electrochemical reaction and is the core component of the MEA; the proton exchange membrane provides a separator between the anode and cathode and also provides a channel for proton transport. Based on the cooling method, proton exchange membrane fuel cells can be divided into liquid-cooled and air-cooled types.

[0003] During the operation of a liquid-cooled fuel cell, approximately 40-60% of the chemical energy is dissipated as heat. If this heat accumulates in the stack, the stack temperature will continuously rise, not only reducing the fuel cell's efficiency but also potentially causing the membrane electrode assembly to burn through due to localized overheating, leading to battery failure. Therefore, heat dissipation measures are essential for the battery.

[0004] In related technologies, the cooling medium typically flows from one side of the fuel cell stack to the other to remove the heat generated by the reaction. However, the heat energy from the reaction in the fuel cell stack is generally concentrated at the center of the battery plates, making the temperature at the center of the fuel cell stack often higher than the temperature at the edges. Therefore, this heat dissipation method cannot ensure that the center and edges of the fuel cell stack are cooled uniformly, resulting in poor overall thermal uniformity of the fuel cell stack. Summary of the Invention

[0005] This disclosure provides a fuel cell unit and a fuel cell stack to solve the technical problem of poor thermal uniformity in traditional fuel cell stacks.

[0006] Therefore, in a first aspect, a fuel cell unit includes: Two electrode plates, each including a gas flow channel surface and a liquid flow channel surface arranged opposite to each other. The gas flow channel surface includes multiple gas flow channel units, which allow gas to flow from the center to the edge, and the multiple gas flow channel units are arranged in an array. The liquid flow channel surface includes multiple liquid flow channel units, which are arranged in a one-to-one correspondence with the multiple gas flow channel units; and... The membrane electrode assembly is located between the gas flow channels of the two electrode plates.

[0007] In one possible implementation, the gas flow channel unit includes a first gas flow channel and a second gas flow channel that are connected. The inlet end of the first gas flow channel is located at the edge of the gas flow channel unit, and the outlet end of the first gas flow channel is located at the center of the gas flow channel unit. The second gas flow channel is arranged around the periphery of the first gas flow channel, and the flow channel length of the second gas flow channel is greater than the flow channel length of the first gas flow channel.

[0008] In one possible implementation, the cross-section of the first gas flow channel is larger than the cross-section of the second gas flow channel.

[0009] In one possible implementation, the second gas flow channel is provided in two sets, and the two sets of second gas flow channels are symmetrically distributed along the axial direction of the first gas flow channel.

[0010] In one possible implementation, the second gas flow channel includes multiple branch channels and multiple confluence channels, the multiple confluence channels being distributed at intervals along the axial direction of the first gas flow channel, the branch channels being used to connect the first gas flow channel and the confluence channels, and to connect two adjacent confluence channels. The length of the branch channel farther from the outlet end of the first gas channel is greater than the length of the branch channel closer to the outlet end of the first gas channel.

[0011] In one possible implementation, the gas flow channel unit is shaped as any one or a combination of rectangle, triangle, circle, semicircle, trapezoid, and rhombus.

[0012] In one possible implementation, multiple gas flow channel units are arranged in a matrix array. The gas flow channel surface also includes an inflow main channel, multiple inflow auxiliary channels, and an outflow channel. The inflow main channel symmetrically separates the multiple gas flow channel units. The multiple inflow auxiliary channels are distributed side by side at intervals along the axial direction of the inflow main channel. The inflow auxiliary channels have multiple outflow ports. Each outflow port corresponds to one gas flow channel unit. The outflow end of the gas flow channel unit is connected to the outflow channel.

[0013] In one possible implementation, the outflow channel has an outflow main channel and multiple outflow auxiliary channels, with one inflow auxiliary channel corresponding to two outflow auxiliary channels. The outflow auxiliary channels are symmetrically distributed on both sides of the inflow main channel. The outflow auxiliary channels have multiple inflow ports, with one inflow port corresponding to one gas flow channel unit. The outflow ends of the multiple outflow auxiliary channels are connected to the outflow main channel. The outflow and inflow main channels are located on opposite sides of the gas flow channel surface.

[0014] In one possible implementation, the liquid flow channel unit includes a first liquid flow channel, a second liquid flow channel, and an adjusting member. The first liquid flow channel extends from the side edge of the liquid flow channel unit to the center position, and the second liquid flow channel is disposed around the periphery of the first liquid flow channel, and the second liquid flow channel and the first liquid flow channel are connected at the center position. An adjusting element is disposed in the first liquid flow channel to increase the flow rate of the liquid entering the second liquid flow channel according to the temperature rise at the center position; or to decrease the flow rate of the liquid entering the second liquid flow channel according to the temperature drop at the center position.

[0015] Secondly, this disclosure also provides a fuel cell stack, including a plurality of fuel cell units as described above, wherein the plurality of fuel cell units are stacked sequentially.

[0016] According to the fuel cell unit and fuel cell stack provided in this disclosure, the fuel cell unit includes: two electrode plates, each electrode plate including a gas flow channel surface and a liquid flow channel surface arranged opposite to each other. The gas flow channel surface includes multiple gas flow channel units, which allow gas to flow from the center to the edge, and the multiple gas flow channel units are arranged in an array. The liquid flow channel surface includes multiple liquid flow channel units, which are arranged one-to-one with the multiple gas flow channel units. A membrane electrode assembly is also provided, disposed between the gas flow channel surfaces of the two electrode plates. This technical solution optimizes the structural layout of the flow channels on the electrode plates, decentralizing the fuel gas flow channels to improve the traditional heat generation structure where the fuel gas generates high heat at the center of the electrode plate and low heat generation at the edge. This allows the high heat generation points of the fuel gas to be evenly distributed across the electrode plates, adjusting the thermal balance of the electrode plates on the fuel gas side. Simultaneously, the decentralized layout of the cooling liquid flow channels on the electrode plates allows for targeted individual heat dissipation for each gas flow channel unit, thereby improving the heat dissipation balance of the fuel cell. In this way, the fuel cell unit can achieve a dual decentralized layout on both the gas and coolant sides, which can optimize the thermal balance performance of the plates from at least two aspects: heat generation and heat dissipation. Attached Figure Description To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort. In addition, in the drawings, the same parts use the same reference numerals, and the drawings are not drawn to scale.

[0017] Figure 1 An exploded perspective view of a fuel cell unit provided in an embodiment of this disclosure; Figure 2 A partial cross-sectional view of the gas flow channel surface provided in an embodiment of this disclosure; Figure 3 A full cross-sectional view of the gas flow channel surface provided in an embodiment of this disclosure; Figure 4 A partial enlarged view of the gas flow channel unit provided in an embodiment of this disclosure; Figure 5 A partial cross-sectional view of the liquid flow channel surface provided in an embodiment of this disclosure; Figure 6 A full cross-sectional view of the liquid flow channel surface provided in an embodiment of this disclosure; Figure 7 This is a partial enlarged view of the liquid flow channel unit provided in an embodiment of this disclosure.

[0018] Explanation of reference numerals in the attached figures: 100, electrode plate; 101, gas flow channel surface; 102, liquid flow channel surface; 110, gas flow channel unit; 111, first gas flow channel; 112, second gas flow channel; 1121, branch channel; 1122, confluence channel; 120, liquid flow channel unit; 121, first liquid flow channel; 122, second liquid flow channel; 123, regulating component; 131, inflow main channel; 132, inflow auxiliary channel; 133, outflow channel; 1331, outflow main channel; 1332, outflow auxiliary channel; 200. Membrane electrode assembly. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0020] See Figures 1 to 7 This disclosure provides a fuel cell unit, including: Two electrode plates 100, each including a gas flow channel surface 101 and a liquid flow channel surface 102 disposed opposite to each other. The gas flow channel surface 101 includes multiple gas flow channel units 110, which allow gas to flow from the center to the edge, and the multiple gas flow channel units 110 are arranged in an array. The liquid flow channel surface 102 includes multiple liquid flow channel units 120, which are arranged in a one-to-one correspondence with the multiple gas flow channel units 110. The membrane electrode assembly 200 is disposed between the gas flow channel surfaces 101 of the two electrode plates 100.

[0021] In this embodiment, the flow channel structures on the fuel gas flow channel surface 101 and the coolant liquid flow channel surface 102 on the electrode plate 100 are optimized to optimize the thermal balance of the fuel cell unit from at least simultaneously the heat generation and heat dissipation sides. Specifically, multiple gas flow channel units 110 are configured on the gas flow channel surface 101 to break away from the traditional arrangement of only one gas flow channel unit 110 on the electrode plate 100. This avoids the accumulation of heat generated on the gas flow channel side at the center of the electrode plate 100, while the liquid flow channel side fails to dissipate heat from the center of the electrode plate 100 in a timely manner, thus preventing localized overheating and damage to the electrode plate 100. The arrangement of multiple gas flow channel units 110 disperses the high heat generation points on the gas flow channel surface 101 side to different positions on the electrode plate 100, avoiding accumulation at the center of the electrode plate 100. In this way, on the one hand, by dispersing the fuel gas into different gas flow channel units 110 for reaction, the maximum heat generation in each gas flow channel unit 110 can be effectively reduced, making the heat generation on the entire electrode plate 100 more balanced. On the other hand, by decentralizing the gas flow channels on the fuel gas side, the heat generation structure of traditional fuel gas, which has high heat generation at the center of the electrode plate 100 and low heat generation at the edges, can be effectively improved. This allows the high heat generation points of the fuel gas to be evenly distributed on the electrode plate 100, improving the thermal balance on the fuel gas side and increasing the utilization rate of the fuel gas.

[0022] Furthermore, multiple liquid flow channel units 120 are configured on the liquid flow channel surface 102, with each liquid flow channel unit 120 corresponding to a gas flow channel unit 110. This allows for targeted heat dissipation of heat from a gas flow channel unit 110 through a liquid flow channel unit 120, achieving decentralized heat dissipation of the electrode plate 100 and improving the heat dissipation uniformity of the fuel cell unit. Therefore, by simultaneously decentralizing the layout on both the fuel gas side and the coolant side of the fuel cell unit, its thermal balance performance can be improved from at least two aspects: heat generation and heat dissipation.

[0023] Furthermore, the gas flow channel unit 110 on the fuel gas side is configured as a flow channel structure that allows gas to flow from the center to the edge. In this way, the heat generation high point of the gas flow channel unit 110 is located at the center of the gas flow channel unit 110, so that the heat generation of the fuel cell can diffuse from the center outward, thereby improving the thermal balance of each gas flow channel unit 110.

[0024] Specifically, the gas flow channels 101 of the two electrode plates 100 are respectively disposed on opposite sides of the membrane electrode assembly 200 to form spaces for fuel gas reaction on both sides of the membrane electrode assembly 200. Specifically, the gas flow channel surface 101 of one electrode plate 100 is used for hydrogen flow, and the gas flow channel surface 101 of the other electrode plate 100 is used for air (oxygen) flow. Hydrogen gas is converted into hydrogen ions at the membrane electrode assembly 200 and passes through the membrane electrode assembly 200. Air (oxygen) reacts with the hydrogen ions passing through the membrane electrode assembly 200 to generate water, thus completing the energy conversion of fuel gas. The liquid flow channels 102 of the two electrode plates 100 are respectively disposed on opposite sides of the membrane electrode assembly 200 and are used to combine with the liquid flow channel surface 102 of the electrode plate 100 of another fuel cell unit to form a liquid flow channel system for coolant flow, which is used to dissipate heat from the electrode plates 100.

[0025] See Figure 4 In one possible implementation, the gas flow channel unit 110 includes a first gas flow channel 111 and a second gas flow channel 112 that are connected. The inlet end of the first gas flow channel 111 is located at the edge of the gas flow channel unit 110, and the outlet end of the first gas flow channel 111 is located at the center of the gas flow channel unit 110. The second gas flow channel 112 is disposed around the periphery of the first gas flow channel 111, and the flow length of the second gas flow channel 112 is greater than the flow length of the first gas flow channel 111.

[0026] In this embodiment, the flow channel structure of the gas flow channel unit 110 is optimized. Specifically, a first gas flow channel 111 and a second gas flow channel 112 are configured. The first flow channel delivers the fuel gas to the center position of the gas flow channel unit 110, and the second gas flow channel 112 diverts the gas at the center position to other positions of the gas flow channel unit 110. The flow channel length of the second gas flow channel 112 is greater than the flow channel length of the first gas flow channel 111, so as to prolong the contact time between the fuel gas flowing out from the center position and the membrane electrode assembly 200, improve the reaction time of the fuel gas, and improve the utilization rate of the fuel gas.

[0027] For example, but not limited to, the first gas flow channel 111 is a direct flow channel, with its two ends connected to the side edge and center of the electrode plate 100, respectively, so as to deliver the fuel gas to the center of the gas flow channel unit 110 for reaction in a shorter time. The second gas flow channel 112 is a curved flow channel, which is distributed around the first gas flow channel 111 to other positions of the electrode plate 100, so as to increase the flow time of the fuel gas in the gas flow channel unit 110, increase the contact area between the fuel gas and the membrane electrode assembly 200, and improve the utilization rate of the fuel gas.

[0028] In one possible implementation, the cross-section of the first gas flow channel 111 is larger than the cross-section of the second gas flow channel 112.

[0029] In this embodiment, the specific parameters of the first gas flow channel 111 and the second gas flow channel 112 are configured. Specifically, the size of the first gas flow channel 111 is set to be larger than the size of the second gas flow channel 112, so that the gas flow rate entering the center position is greater than the gas flow rate exiting the center position. In this way, the reaction of the gas flow channel unit 110 diffuses from the center to the edge, thereby allowing the heat generated by the gas flow channel unit 110 to diffuse from the center to the edge.

[0030] In one possible implementation, the second gas flow channel 112 is provided in two sets, and the two sets of second gas flow channels 112 are symmetrically distributed along the axial direction of the first gas flow channel 111.

[0031] In this embodiment, the flow channel structure of the second gas flow channel 112 is optimized. Specifically, two sets of symmetrically distributed second gas flow channels 112 are provided. These second gas flow channels 112 guide the unreacted fuel gas at the central position to other positions in the gas flow channel unit 110 to undergo ion exchange with the membrane electrode assembly 200, completing the reaction and energy conversion of the fuel gas. The symmetrical structural arrangement is beneficial to further improve the stability and uniformity of gas flow in the gas flow channel unit 110.

[0032] See Figure 2 and Figure 3 In one possible implementation, the second gas flow channel 112 includes a plurality of branch channels 1121 and a plurality of confluence channels 1122. The plurality of confluence channels 1122 are distributed at intervals along the axial direction of the first gas flow channel 111. The branch channels 1121 are used to connect the first gas flow channel 111 and the confluence channels 1122, and to connect two adjacent confluence channels 1122. The length of the branch channel 1121, which is farther from the outlet end of the first gas flow channel 111, is greater than the length of the branch channel 1121, which is closer to the outlet end of the first gas flow channel 111.

[0033] In this embodiment, the flow channel structure of the second gas flow channel 112 is optimized. Specifically, the second gas flow channel 112 is configured as a combined flow channel structure including at least a plurality of branch channels 1121 and a plurality of confluence channels 1122. The branch channels 1121 are used to guide fuel gas to other locations in the gas flow channel unit 110, and the confluence channels 1122 are used to collect the fuel gas in the branch channels 1121 and further guide the general flow direction of the fuel gas on the electrode plate 100.

[0034] Furthermore, multiple manifolds 1122 are spaced apart below the first gas flow channel 111, and are coaxially arranged with the first gas flow channel 111. Multiple branch channels 1121 are arranged in a curved manner between the first gas flow channel 111 and the manifolds 1122, and between adjacent manifolds 1122. For example, but not limited to, two symmetrically arranged branch channels 1121 are arranged between the first gas flow channel 111 and an adjacent manifold 1122, and two symmetrically arranged branch channels 1121 are arranged between adjacent manifolds 1122. In the direction of fuel gas flow, the length of the branch channels 1121 increases, and the contact area between the fuel gas and the membrane electrode assembly 200 is larger in the branch channels 1121 closer to the outlet end of the gas flow channel unit 110.

[0035] In one possible implementation, the gas flow channel unit 110 is shaped as any one or a combination of rectangle, triangle, circle, semicircle, trapezoid, and rhombus.

[0036] In this embodiment, the shape of the gas flow channel unit 110 is optimized. Specifically, the shape of the gas flow channel unit 110 can be configured in various shapes, and the arrangement shape of the gas flow channel unit 110 is not limited here. Preferably, the gas flow channel unit 110 is configured as a square structure.

[0037] In one possible implementation, multiple gas flow channel units 110 are arranged in a matrix array. The gas flow channel surface 101 also includes an inflow main channel 131, multiple inflow auxiliary channels 132, and an outflow channel 133. The inflow main channel 131 symmetrically separates the multiple gas flow channel units 110. The multiple inflow auxiliary channels 132 are arranged side by side at intervals along the axial direction of the inflow main channel 131. The inflow auxiliary channels 132 have multiple outflow ports, and each outflow port corresponds to a gas flow channel unit 110. The outflow end of the gas flow channel unit 110 is connected to the outflow channel 133.

[0038] In this embodiment, the flow channel structure on the gas flow channel surface 101 is arranged. Specifically, multiple gas flow channel units 110 are configured in a matrix form with multiple rows and columns. This matrix form of gas flow channel units 110 includes a multi-row, multi-column structure. Each row includes multiple gas flow channel units 110, and each column includes multiple gas flow channel units 110. For this multi-row, multi-column gas flow channel unit 110 layout structure, a main inflow channel 131 and multiple auxiliary inflow channels 132 system are configured to connect the inflow end of each gas flow channel unit 110. Specifically, the main inflow channel 131 divides the electrode plate 100 into two symmetrical parts. Each auxiliary inflow channel 132 is symmetrically connected to the main inflow channel 131 and corresponds to a row of multiple gas flow channel units 110 structures. The outflow port of each auxiliary inflow channel 132 is adapted to the number of gas flow channel units 110 in a row. Each gas flow channel unit 110 is connected to the outflow channel 133 at its outflow end to recover and reuse residual fuel gas.

[0039] For example, but not limited to, there are a total of 12 gas flow channel units 110, with 4 gas flow channel units 110 arranged at intervals in each row and 3 gas flow channel units 110 arranged at intervals in each column. There is one main inflow channel 131 and 3 auxiliary inflow channels 132. Each auxiliary inflow channel 132 has 4 outflow ports, and each outflow port is connected to the inflow end of a gas flow channel unit 110.

[0040] Of course, in other embodiments, the plurality of gas flow channel units 110 may also be in the shape of any one of triangle, circle, semicircle, trapezoid and rhombus, which will not be described in detail here.

[0041] In one possible implementation, the outflow channel 133 has an outflow main channel 1331 and a plurality of outflow auxiliary channels 1332. One inflow auxiliary channel 132 is provided corresponding to two outflow auxiliary channels 1332. The outflow auxiliary channels 1332 are symmetrically distributed on both sides of the inflow main channel 131. The outflow auxiliary channels 1332 have a plurality of inflow ports. One inflow port is provided corresponding to a gas flow channel unit 110. The outflow ends of the plurality of outflow auxiliary channels 1332 are connected to the outflow main channel 1331. The outflow main channel 1331 and the inflow main channel 131 are arranged on opposite sides of the gas flow channel surface 101.

[0042] In this embodiment, the specific flow channel structure of the outflow channel 133 is arranged. Specifically, for a multi-row, multi-column structure arranged in a matrix, the outflow channel 133 is configured as an outflow channel 133 system including at least one main outflow channel 1331 and multiple auxiliary outflow channels 1332. The auxiliary outflow channels 1332 are symmetrically distributed on opposite sides of the main inflow channel 131, and the main outflow channel 1331 is disposed at the outflow end of the electrode plate 100.

[0043] For example, but not limited to, there are a total of 12 gas flow channel units 110, with 4 gas flow channel units 110 arranged at intervals in each row and 3 gas flow channel units 110 arranged at intervals in each column. There is one main outflow channel 1331 and 6 auxiliary outflow channels 1332. Each auxiliary outflow channel 1332 has 2 inflow ports, and each inflow port is connected to the outflow end of a gas flow channel unit 110.

[0044] See Figures 5 to 7 In one possible implementation, the liquid flow channel unit 120 includes a first liquid flow channel 121, a second liquid flow channel 122, and an adjusting member 123. The first liquid flow channel 121 extends from the side edge of the liquid flow channel unit 120 to the center position, and the second liquid flow channel 122 is disposed around the periphery of the first liquid flow channel 121, and the second liquid flow channel 122 and the first liquid flow channel 121 are connected at the center position. The regulating member 123 is disposed in the first liquid flow channel 121 to increase the flow rate of the liquid entering the second liquid flow channel 122 according to the temperature rise at the center position; or to decrease the flow rate of the liquid entering the second liquid flow channel 122 according to the temperature drop at the center position.

[0045] In this embodiment, the liquid flow channel structure arranged on the liquid flow channel surface 102 is optimized. Specifically, the liquid flow channel unit 120 is configured as a combination of at least a first liquid flow channel 121, a second liquid flow channel 122, and an adjusting member 123. The first liquid flow channel 121 extends from the side edge of the liquid flow channel surface 102 to the center position to allow the cooling medium entering the liquid flow channel unit 120 to pass into the center position for heat dissipation of the electrode plate 100; the second liquid flow channel 122 is arranged around the periphery of the first liquid flow channel 121 to dissipate heat from the periphery of the liquid flow channel unit 120 and to lead the cooling medium out of the liquid flow channel unit 120, thereby realizing the recovery and circulation of the cooling medium.

[0046] Specifically, the cooling medium enters the liquid flow channel unit 120 from the inlet end of the first liquid flow channel 121, and then flows directly to the center of the liquid flow channel unit 120, where the cooling medium has a lower temperature. Then, at the center, the lower-temperature cooling medium undergoes efficient heat exchange with the electrode plate 100, causing the temperature of the electrode plate 100 to decrease and the temperature of the cooling medium to increase. The heated cooling medium then enters the second liquid flow channel 122 and, guided by the second liquid flow channel 122, flows through other locations of the liquid flow channel unit 120, where it undergoes effective heat exchange with the electrode plate 100, causing the temperature of the cooling medium flowing out of the second liquid flow channel 122 to increase further and the temperature of the electrode plate 100 to decrease further. The reheated cooling medium then flows out of the liquid flow channel unit 120 and enters the liquid recovery system. In this way, the decentralized liquid flow channel unit 120 can effectively exchange heat with the electrode plate 100 corresponding to the gas flow channel unit 110, thereby achieving balanced cooling and heat dissipation of the entire electrode plate 100, which is beneficial to extending the service life of the electrode plate 100.

[0047] For example, but not limited to, the regulating element 123 is a flow-blocking airbag disposed on the side of the first liquid flow channel 121 near the second liquid flow channel 122. The flow-blocking airbag is filled with gas and can expand or contract according to temperature increases or decreases, thereby regulating the flow rate of the cooling medium flowing from the first liquid flow channel 121 into the second liquid flow channel 122, thus adjusting the flow rate of the cooling medium entering the second liquid flow channel 122. It should be understood that the regulating element 123 should remain connected to the inner wall of the first liquid flow channel 121 to prevent it from being washed away by the cooling medium within the liquid flow channel.

[0048] Of course, in other embodiments, the adjusting element 123 may also be made of an expanding material, such as an expanding alloy.

[0049] Secondly, this disclosure also provides a fuel cell stack, including a plurality of fuel cell units as described above, wherein the plurality of fuel cell units are stacked sequentially. The specific structure of the fuel cell unit is the same as described in the above embodiments. Since this fuel cell stack adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, and will not be described in detail here.

[0050] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0051] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fuel cell unit, characterized in that, include: Two electrode plates, each comprising a gas flow channel surface and a liquid flow channel surface arranged opposite to each other. The gas flow channel surface includes multiple gas flow channel units, which allow gas to flow from a center position to the edge. These multiple gas flow channel units are arranged in an array. The liquid flow channel surface includes multiple liquid flow channel units, each corresponding to one of the multiple gas flow channel units. A membrane electrode assembly is disposed between the gas flow channels of the two electrodes; The gas flow channel unit includes a first gas flow channel and a second gas flow channel that are connected. The inlet end of the first gas flow channel is located at the edge of the gas flow channel unit, and the outlet end of the first gas flow channel is located at the center of the gas flow channel unit. The second gas flow channel is arranged around the periphery of the first gas flow channel, and the flow channel length of the second gas flow channel is greater than the flow channel length of the first gas flow channel. The cross-section of the first gas flow channel is larger than the cross-section of the second gas flow channel; The second gas flow channel is provided in two sets, and the two sets of the second gas flow channels are symmetrically distributed along the axial direction of the first gas flow channel; The liquid flow channel unit includes a first liquid flow channel, a second liquid flow channel, and an adjusting component. The first liquid flow channel extends from the side edge of the liquid flow channel unit to the center position. The second liquid flow channel is arranged around the periphery of the first liquid flow channel, and the second liquid flow channel and the first liquid flow channel are connected at the center position. The regulating element is disposed in the first liquid flow channel to increase the flow rate of the liquid entering the second liquid flow channel according to the temperature rise at the center position; or to decrease the flow rate of the liquid entering the second liquid flow channel according to the temperature drop at the center position.

2. The fuel cell unit according to claim 1, characterized in that, The second gas flow channel includes multiple branch channels and multiple confluence channels. The multiple confluence channels are distributed at intervals along the axial direction of the first gas flow channel. The branch channels are used to connect the first gas flow channel and the confluence channels, and to connect two adjacent confluence channels. The length of the branch channel farther from the outlet end of the first gas channel is greater than the length of the branch channel closer to the outlet end of the first gas channel.

3. The fuel cell unit according to claim 1, characterized in that, The shape of the gas flow channel unit is any one or a combination of rectangle, triangle, circle, semicircle, trapezoid and rhombus.

4. The fuel cell unit according to claim 1, characterized in that, Multiple gas flow channel units are arranged in a matrix array. The gas flow channel surface also includes an inflow main channel, multiple inflow auxiliary channels, and an outflow channel. The inflow main channel symmetrically separates the multiple gas flow channel units. The multiple inflow auxiliary channels are distributed side by side at intervals along the axial direction of the inflow main channel. Each inflow auxiliary channel has multiple outflow ports. Each outflow port corresponds to one gas flow channel unit. The outflow end of each gas flow channel unit is connected to the outflow channel.

5. The fuel cell unit according to claim 4, characterized in that, The outflow channel has a main outflow channel and multiple auxiliary outflow channels. One auxiliary inflow channel corresponds to two auxiliary outflow channels. The auxiliary outflow channels are symmetrically distributed on both sides of the main inflow channel. Each auxiliary outflow channel has multiple inflow ports. One inflow port corresponds to one gas flow channel unit. The outflow ends of the multiple auxiliary outflow channels are connected to the main outflow channel. The outflow main channel and the inflow main channel are arranged on opposite sides of the gas flow channel surface.

6. A fuel cell stack, characterized in that, It includes a plurality of fuel cell units as described in any one of claims 1 to 5, wherein the plurality of fuel cell units are stacked in sequence.

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